The present invention relates to data recording technology for recording data to disk-type recording media such as an optical disk, and more particularly to data recording technology for recording moving images imaged by imaging means and sound from sound collecting means as data to an optical disk.
A CD player for playing back digital audio data from compact disks (CD) is an example of a disk playback device for playing back digital signals from a disk-type recording medium. Using an optical head, the CD player obtains the playback signal by reading the differences in reflectance of the pits and lands, formed on the disk in advance.
A disk playback device, using an optical head for playing back signals from a disk, such as this CD player, has better features, such as random access, than playback devices using tape-type recording media. Further, because the recording media and the optical heads are not in contact, there is no deterioration of the recording medium and reliability is very high.
However, such disk players have problems that make it impossible to read and reproduce the recorded data correctly (for example, the sound will drop out when reproduced with a CD player) because dust and defects on the disk or electrical noise and vibration reduce the signal quality of the optical heads reading the signal from the disk. This type of problem also occurs in disk recording devices. In disk recording devices, dust and defects on the disk or electrical noise and vibrations make it impossible to normally extend the recording signal from the optical heads to the disk, and a proper recording cannot be made on the disk.
Conventionally, these problems have been resolved with a “retry operation” wherein locations (tracks) to which the optical heads could not record are scanned again and the same recording signal is re-recorded.
With a retry operation, the recorded data can be recorded on a disk with as high fidelity as is possible because the head returns to the location directly preceding the location that could not be recorded and carries out correct recording once again. As a result, these means are effective for recording media which can be overwritten any number of times. However, for disk media on which data can be recorded one time only, such as CD-R (compact disk-recordable) and DVD-R (digital versatile disc-recordable), the retry method is not effective. A good recording cannot be made to a disk when correct recording has not been made to locations which have been written to once because there can be no correction re-recording. Patent application JP 2001-171890 has already been filed as related art.